The Amsler Chart or Amsler Grid is an essential tool for detecting changes in the macular and foveal areas of the eye, which may be difficult, or in some instances impossible, to detect by any other means. The Amsler Manual is a set of Amsler Charts, provided with detailed instructions on how to conduct screenings using the chart, as well as information on how to interpret the results.
About the Amsler Chart
The Amsler Chart is a screening tool that can be used to test for changes in the macular and foveal areas of the eye. It has been shown to detect changes in these specific areas of the eye that may be missed when other screening methods are employed. It is particularly useful for detecting the first signs of age-related macular degeneration (AMD), a condition that can be slowed or even halted if detected in the early stages.
The chart consists of a fine, black-outlined grid printed on white paper. The very centre of the grid contains a small, solid black dot, which the test subject uses as a focal target during the screening. The Amsler Chart grid is shown below:
How the Amsler Chart is Used
The test should be conducted in a room with lighting appropriate for reading, and the patient should wear their reading glasses, if applicable. The eyes should be tested separately, so one eye should be covered while the other is tested.
The testing procedure starts with the examiner presenting the grid to the patient at a distance of approximately 35.5 - 40.5cm from their eye. The patient will be instructed to keep their eye focused on the dot in the centre of the grid. While keeping their eye on the dot, the patient will then be asked to report on a number of observations, namely:
- Whether the lines of the grid appear wavy, blurred or distorted
- Whether all of the boxes of the grid are square and the same size
- Whether there are any missing or dark areas in the grid
- Whether or not they can see all of the corners and sides of the grid
Features of the Amsler Manual
The Amsler Manual is a full set of instructions for conducting screening using the Amsler Chart. It is supplied with Amsler Charts, as well as a guide to interpreting the test results.